Philip Kotler said that Marketing was all about satisfying needs and wants through an exchange process. I like another definition by The Chartered Institute of Marketing where they have defined it as the management process responsible for identifying, anticipating and satisfying customer requirements profitably. There would be others too and I am sure people would have studied them.
So as per concept there is no denying that Sales is a function under the umbrella of Marketing. Marketing to me is the whole end to end process of understanding needs, developing products and services to satisfy those needs, reaching them to the customer, support, maintaining relationships. It would also include market analysis, branding, promoting, product management and almost everything to do with a customer. In spite of views that may not agree with mine I am quite unwilling to change my stand on this!!
For people who think otherwise it is due to the perceptions that dictate their views. They would have been exposed to the fact that typically in most organizations you have a separate Sales Department and a separate Marketing Department.
Typically the marketing department in most situations carries out the marketing support functions like advertising, brand building and promotions. Some of them also bring in Product Management under this department though I have seen situations where Product Management is a separate group and they are responsible for the whole cycle for that particular product. Marketing Dept in the latter companies would perhaps just provide OVERALL Corporate Marketing Support.
Sales is a very important process since it deals with the bottom line(others do too). It consumes a lot of energy in dealing and converting the unknown and also tests the concepts on ground. Most organizations find it easier therefore to separately handle the marketing portions(other than sales) and sales. There would be aspects of Marketing that is broken up and handled by different departments or units. What is however important is that all the marketing activities that would include sales need to be in tandem. The entire mega process is marketing while sub processes are delegated to specialized people.
Let’s say there is a marketing project where a new brand of toothpaste has to be introduced you would find even R&D and production people getting involved. If the manufacturing is outsourced your external partner gets involved too.
Therefore without confusing ourselves, like some have already explained, everything has to work together. Every unit has a given deliverable to accomplish. Deliverables could be one time or repeatable. They all contribute to the big M.
It depends upon the “culture/direction from top management” on how the organization is structured and how processes will be carried out. The debate that carries on therefore is purely semantics and not worth considering.